Each camera (and its lens mount) is designed with a specific 'flange distance', which is the distance from the exit end of the lens to the sensor (or film). Of course, DSLRs with mirrors have been designed with plenty of room for the mirror to move in the shutter box, without hitting the lens.
For lenses that have been designed for a longer flange distance, its pretty simple to include that distance in an adapter. But for lenses that have been designed with a smaller flange distance, it is almost impossible to adapt: the focal point will be outside of the range of the lens, and it might hit the mirror.
The wikipedia article on flange distance lists the distance of a Sony E-mount lens as 18mm. This is very close to the sensor, as the Sony does not have a mirror. However, the Canon EOS EF lens flange distance is 44mm, meaning that the lens is 44mm away from the sensor. A Sony lens that requires only 18mm would need to be closer to the Canon sensor than is possible — it would hit the mirror. If an adapter ring were to be created, its depth would add even more distance from the sensor, where the Sony lens is designed to focus 18mm way, not 44+x mm away.
Therefore, there is no way to adapt a Sony E-mount to a Canon EOS camera, but you could adapt a Canon lens to the Sony camera.